Process of making alkyl amino carbinols



Patented Jan. 9, 1934 UNITED STATES PATENT OFFICE PROCESS OF MAKING ALKYL AMINO CARBINOLS Frederick H. Kranz, Buffalo, N. Y., assignor to National Aniline & "Chemical Co. Inc., New York, N. Y., a corporation of New York No Drawing. Application February '7, 1930 Serial No. 426,595

Claims. (Cl. 260 -64).

methane with lead peroxide in the presence of a 70 dilute aqueous solution containing a mixture of hydrochloric and acetic acids. The tetra ethyl diamino diphenyl carbinol thus produced is a crude product and the yield, based on the pure carbinol present, is ordinarily about to per cent. of the theoretical. It has also been proposed to prepare tetra methyl-4.4'-diamino diphenyl carbinol in a similar manner, and the yield of carbinol thus obtained, based on pure product produced, is likewise comparatively low, it being usually about to '78 per cent. of theory.

It is an object of the invention to provide a process for the production of alkyl diamino diaryl carbinols which may be readily practiced on a commercial scale with efliacy and produce a product at a reduced cost.

Another object of the invention is to provide a process for the manufacture of alkyl diamino diaryl carbinols, particularly the tetra alkyl 4.4-diamino diaryl carbinols whereby these compounds may be produced in increased yields and with improved quality.

Other'objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others thereof, which will be exemplified in the process hereinafter disclosed, and the scope of the invention will be indicated in the claims.

In the practice of the invention an improvement in quality and an increase in yield of alkyl diamino diaryl carbinols can be obtained by carrying out the oxidation of the corresponding alkyl diamino diaryl methanes with a suit- 05' able oxidant in the presence of formic acid; thus,

for example, tetra ethyl (methyl, propyl, etc.) diamino diphenyl carbinol may be obtained by oxidizing tetra ethyl (methyl, propyl, etc.) diamino diphenyl methane with lead peroxide in T the presence of formic acid.

Further, in the practice of the present invention, the alkyl diamino diaryl methane body may be suspended, or preferably, dissolved in an excess of formic acid, then diluted with water and to the diluted aqueous suspension or solution, 5

maintained at a temperature not higher than ordinary or room temperature, or better, at about 0 to 5 0., there is added with good stirring, a metal dioxide as an oxidant, e. g. lead peroxide,

manganese dioxide, etc.a theoretical amount 10,

of oxidant is preferably employed. When the oxidation is complete or substantially so, the resulting carbinol is isolated in any suitable manner. Y

The quality of product and the yields of the 15 carbinol body which I have obtained in carrying out the oxidation in this way are considerably higher than those obtainable by any analogous method heretofore proposed,'in so far'as I am aware.

As-an illustrative embodiment of a manner in which the invention may be carried into prac-- tice, the following example is presented: the parts are by weight. 1

Example: "650 partstetra ethyl-4.4-diamino diphenyl methane are dissolved in 750 parts of formic acid of 90% strength. The resulting solution is added to a well-stirred mixture of 11,000 parts water and 7,000 parts ice. 502 parts of lead peroxide (on a 100 per cent. basis) in the form of a thin aqueous paste is then quickly added, with good stirring, to the tetra ethyl diamino diphenyl methane solution, the temperature of the reaction mixture being maintained around 0 C. by the presence of ice. After all of the lead peroxide is added, the mixture is further agitated for about 10-15 minutes or until the oxidation to the carbinol is practically complete, the temperature being maintained at about 0 C. 400 parts of sodium sulfate, calculated as the anhydrous salt, are then added to precipitate the lead as lead sulfate. After stirring for a short time,'e. g., 15-30 minutes, the lead sulfate is filtered off and to the cold filtrate there is added a slight excess of a caustic soda solution. The tetra ethyl diamino diphenyl carbinol which separates out is filtered off and washed with water. The yield, based on the pure carbinol present, is about 80 per cent.

If, in the above example, an equivalent amount of tetra methyl-4.4-diamino diphenyl methane be used in place of the tetra ethyl body, a yield of about 85-88 per cent. of tetra methyl diamino diphenyl carbinol can be obtained. This yield is about 10-12 per cent. higher than when a mixture of hydrochloric and acetic acids is used as the acid medium.

It may be pointed out that other acids, e. g. hydrochloric acid, may be used, if desired, in conjunction with formic acid but their presence is not necessary. Instead of using sodium sulfate to precipitate the lead, other soluble sulfate, or sulfuric acid, may be employed.

The present invention is applicable to the production of other tetra-alkyl diamino diaryl methanes by the oxidation of their corresponding methane bodies in the presence of formic acid, for example, methane bodies having the following probable general formula when R and R signify the same or different aryl residues, more particularly an aryl residue of the benzene series, e. g. CsH4, CsH3(CH3)-., CsH2(CH3)2-, etc. and W, X, Y, and Z denote the same or different alkyl groups, e. g. CH3, C2H5, CsI-I'l, C4H9, etc.

Since certain changes in carrying out the above process may be made without departing from its scope, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described.

I claim:

1. A process for the production of tetra ethyl- 4.4-diamino diphenyl carbinol which comprises dissolving 650 parts of tetra ethyl-4.4'-diamino diphenyl methane in I50 parts of 90% formic acid, diluting the solution with 11,000 parts of water and 7,000 parts of ice, adding 502 parts of lead dioxide, maintaining the solution at a temperature of about 0 C. for 10 to 15 minutesand separating out the carbinol compound formed.

2. In the production of a tetra alkyl diamino diaryl carbinol by a process which includes the interaction of the corresponding tetra alkyl diamino diaryl methane with an oxidizing agent and an acid, the improvement which comprises dissolving the tetra alkyl diamino diaryl methane in strong formic acid, diluting the resulting solution with a weight of water greatly in excess of the weight of the said solution, and treating the resulting dilute solution with the oxidizing agent.

3. In the production of a tetra alkyl-4.4'-diamino diaryl carbinol of the benzene series by a process which includes the interaction of the corresponding tetra alkyl diamino diaryl methane with a metal dioxide and an acid, the improvement which comprises dissolving a tetra alkyl-4.4'-diamino diaryl methane of the benzene series in strong formic acid, diluting the resulting solution with a weight of water greatly in excess of the weight of the said solution, and treating the resulting dilute solution with the metal dioxide.

4.'In the production of a tetra alkyl-4.4-diamino diphenyl carbinol by a process which includes the interaction of the corrresponding tetra a1kyl-4.4-diamino diphenyl methane with a metal dioxide and an acid, the improvement which comprises dissolving the tetra alkyl-4.4- diamino diphenyl methane in strong formic acid, diluting the resulting solution with an amount of Water at least suflicient to reduce the concentration of the diphenyl methane body to about 5 per cent., and. treating the resulting solution with the metal dioxide.

5. In the production or tetra ethyl-4.4'-diamino diphenyl carbinol by a process which includes the interaction of tetra ethyl-4.4'-diamino diphenyl methane with lead peroxide and an acid, the improvement which comprises dissolving the tetra ethyl-4.4-diamino diphenyl methane in a strong formic acid solution containing a weight of formic acid at least about equal to the weight of said diphenyl methane, diluting the resulting solution with an amount of water at least sufficient to reduce the concentration of the diphenyl methane body to about 5 per cent., and treating the resulting solution with lead peroxide while maintaining the solution at a temperature not higher than-about 5 C.

6. In the production of tetra ethyl-4.4'-diamino diphenyl carbinol by a process which includes the interaction of tetra ethyl-4.4- diamino diphenyl methane with lead peroxide and an acid, the improvement which comprises dissolving the tetra ethyl-4.4-diamino diphenyl methane in a strong formic acid solution containing a weight of formic acid in slight excess of the weight of said diphenyl methane, diluting the resulting solution with an ,amount of water adapted to reduce the concentration of tetra ethyl-4.4'-diamino diphenyl methane to between about 5 and about 3 per cent., and quickly adding to the resulting solution substantially the theoretical amount of lead peroxide necessary to oxidize the tetra ethyl-4.4'-diaminodiphenyl methane to the tetra ethyl-4.4-diamino diphenyl carbinol while maintaining the solution at a temperature not higher than about 5 C.

FREDERICK H. KRANZ. 

